Project Summary Monoclonal antibodies (mAbs) are a well-validated drug platform with exquisite specificity, diversity and potency. They offer the lowest-risk class of drug for development through licensure and offer great potential for addressing emerging and re-emerging infectious diseases. To be prepared as threats, like Ebola (EBOV), Marburg (MARV), and Zika viruses, continue to emerge or re-emerge, rapid discovery capabilities are a critical element. One of the best current methods for discovery of potent human mAbs is isolation of peripheral B-cells from survivors/sero-positive individuals for single cell sequencing or hybridoma generation. However, peripheral B-cells are not always easy to obtain and only represent a small percentage of the total B-cell population across all bodily tissues. We have developed an antibody discovery technology in which only serum antibodies are required, i.e. mAb sequences against a given antigen can be sequenced de novo from polyclonal antibody (pAb) pools without the need for sequencing of genetic material. We propose to further refine this novel proteomic approach and apply it towards discovery of new antibodies in serum obtained from EBOV survivors. Here IgGs from survivor plasma will be purified by filovirus glycoprotein antigen specificity and sequenced independently of B-cells. Given our preliminary data, these efforts may yield mAbs that are cross-reactive to ZEBOV, SUDV, BDBV, and possibly MARV. Viable mAbs will ultimately be developed to become pan-EBOV (ZEBOV, SUDV, BDBV) and/or pan-filovirus (EBOV, MARV) therapeutic products. But perhaps the most significant contribution of this work will be to further develop our rapid antibody discovery approach, which may impact drug discovery in nearly all sectors of the mAb industry, including infectious disease.